Windmill Slam
Windmill Slam are Oisin and Denis, a pair of Irish college students with too much time on their hands and some tickets to burn. You might learn something from watching them draft, but you're more likely to choose sides as they argue over plays and picks. You can find them at their youtube channel or on Twitter @WindmillSlamMTG.

MtGNotifier
Can trigger a sound effect when receiving trade requests or messages, and includes hundreds of MtG Symbols for chat and the classifieds. Free to download.

Magic Online Playmats and Other Resources for Limited
This page contains freely downloadable resources, including Magic Online playmats and Magic Online-compatible lists, to help remind you what spells your opponent could cast during your turn with his or her available mana.